Ultrastructure of vacuolated plasma cells in macroglobulinemia associated with production of Mu-chain fragment.
In a unique case of macroglobulinemia associated with the production of mu-chain fragment, the authors observed vacuolated plasma cells (Vac-P) in the bone marrow. Immunofluorescence with anti-mu-chain showed positive staining for the cytoplasm but negative for the vacuoles. On electron microscopic study, clear vacuoles were localized in the vicinity of the Golgi complex, and the contents were amorphous membrane debris and concentric circular structures. The vacuolar membrane was partially disrupted and was contiguous with the outer surface of the concentric circular structure. From the findings, the authors thought these vacuoles were autophagic. Disruption of vacuolar membranes was also demonstrated in three other cases of Vac-P studies with electron microscope. Heterophagy of toxic substances, such as silica or salt or urate, leads to membrane disruption. Vac-P observed in abnormal mu-chain production may produce toxic substances. Once the substance is incorporated into the autophagic vacuole, the vacuolar membrane will be weakened, and the absorption of part of the membrane and cytoplasm or organelles follows.
D000368:Aged; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000096:biosynthesis*; D007148:Immunoglobulin mu-Chains / Q000096:biosynthesis*; D008297:Male; D010950:Plasma Cells / Q000648:ultrastructure*; D014617:Vacuoles / Q000648:ultrastructure; D008258:Waldenstrom Macroglobulinemia / Q000276:immunology / Q000473:pathology*
D007143:Immunoglobulin Heavy Chains; D007148:Immunoglobulin mu-Chains